Merge pull request #2856 from dstufft/support-falsey-cache-dir

Support a falsey cache-dir

Author: dstufft

pip/wheel.py

@@ -55,7 +55,7 @@ def __init__(self, cache_dir, format_control):
         :param format_control: A pip.index.FormatControl object to limit
             binaries being read from the cache.
         """
-        self._cache_dir = os.path.expanduser(cache_dir)
+        self._cache_dir = os.path.expanduser(cache_dir) if cache_dir else None
         self._format_control = format_control
 
     def cached_wheel(self, link, package_name):

tests/unit/test_wheel.py

@@ -397,3 +397,7 @@ class TestWheelCache:
     def test_expands_path(self):
         wc = wheel.WheelCache("~/.foo/", None)
         assert wc._cache_dir == os.path.expanduser("~/.foo/")
+
+    def test_falsey_path_none(self):
+        wc = wheel.WheelCache(False, None)
+        assert wc._cache_dir is None